I. Field of the Invention
The present invention is directed generally to improvements in concrete flooring and, is more particularly directed to improving the qualities of the floor surface related to appearance, durability, safety and reduction of maintenance requirements. The invention is particularly suited to high-traffic concrete floors such as those found in retail warehouse-type establishments.
II. Discussion of Related Art
Retail establishments have unique flooring demands. The floors and floor surfaces must deal with heavy loading, impacts from dropped articles and high traffic which, with other factors, combine to make it extremely difficult for the flooring industry to satisfy the needs of the retailer at a reasonable total cost, i.e., considering both installation and maintenance costs. Conventional retail floor systems of the class of interest normally consist of a slab of conventional load-bearing reinforced concrete covered by vinyl tile or a thin layer of marble or other stone chips set in mortar and polished (terrazzo). These combinations of materials, however, are prone to chipping, cracking and wear resulting in significant on-going repair and including frequent down time and, eventually, costly replacement.
These traditional floor systems require frequent work to sustain an attractive appearance. The maintenance costs of cleaning, waxing and buffing the floor surface may surpass the total cost of the original floor in as short a period as 2 years. In addition, some wax stripping solutions and other surface treating materials may pose environmental hazards and create significant disposal problems. Even with such continual maintenance, waxed floors, over time, tend to yellow and show wear from foot and wheel traffic. A dull appearance further adversely affects lighting levels and overall product presentation in, for example, retail space. Worn and damaged tiles can also result in an unsightly appearance and added safety concerns. Conventional floor surfaces present a danger that customers and employees alike will slip and be injured on wet or waxed floors and the use of these conventional types of floor surfaces may carry higher insurance premiums to the retailer.
In the related art, diverse attempts have been made to control and modify the characteristics including the surface characteristics of concrete flooring, road beds or the like. U.S. Pat. No. 4,746,788, to Shaw et al discloses a process for producing a concrete surface of seeded exposed aggregate using small, rounded aggregate (preferably sand) which is broadcast over the upper surface of the pour and thereafter mixed into the cement paste of the concrete pour matrix. A surface retarder and vapor barrier is applied for a short-term (approximately 4 to 24 hours) and removed and the concrete is thereafter cured by fogging or with a soaker hose and, after approximately 30 days, the surface residue is removed with a steam/acid wash to expose the finished floor. Another method of producing a sand/cement upper surface is disclosed in U.S. Pat. No. 4,281,496, to Danielsson in which larger aggregate is allowed to settle, producing a thin upper layer formed substantially of sanded cement which is thereafter floated to remove surface irregularities. After curing 1 to 5 days, the upper surface is treated in a grinding operation to produce a flat, porous surface having a sanded quality.
Another earlier technique involves the application of an excessively dry top dressing mix while the concrete base is still wet. Water rising from the base concrete penetrates into the topping and the two bond together. The top stratum of the conglomerate can then be wetted and floated to achieve a smooth finish. Such a system is shown by Sloan in U.S. Pat. No. 2,078,289. Reardon, in U.S. Pat. No. 2,853,928, discloses a method for curing concrete in which a dry powder composition is spread over the top of the wet concrete to absorb the excess moisture. The dry powder, however, is not blended into the concrete base and after the concrete is cured for a sufficient length of time, the dry powder is removed by vacuuming or sweeping. That composition is approximately 80 parts silica (SiO.sub.2) and about 20 parts salt (NaCl).
A further patent to Boult (U.S. Pat. No. 2,277,203) discloses yet another technique in which a hardening agent is applied to the surface of a foundation or lower concrete layer which combines with the gauging water or liquid of the foundation layer and a dry ingredient topping of cement and granite or other chips (terrazzo) is applied to the treated surface. The general effect produces a graduated hardening decreasing from the exposed surface of the topping layer downward through that layer and into the upper portions of the foundation layer to produce a hard, wear-resistant upper surface in a monolithic construction.
It is further known to apply a dry shake into a concrete base to control the concrete surface moisture. The dry shake may be incorporated to produce a monolithic cementitious floor by using various processes. None of these prior techniques, however, have resulted in floors having the desired combination of appearance and durability.
From the above, it is apparent that diverse problems confront those who would create more ideal retail or other high-traffic floor systems. One significant goal is to enhance the long-term durability such that the floor system will stand up to many years of daily traffic and the impact of dropped items or the like. In addition, improvements that reduce maintenance costs without sacrificing appearance are of paramount interest. A floor surface able to retain a high gloss finish without the need for additional surface treatment, such as waxing, would be highly desirable. In addition, for safety reasons, it is desirable that the slipperiness of the floor surface be reduced in both the wet and dry conditions. This is true for the safety of customers and employees alike. Thus, a durable, highly reflective or even colored floor of reduced slipperiness which does not require waxing and which maintains a high surface luster to brighten the shopping environment is highly desirable.
While each of the above-enumerated prior patents or other techniques discloses attempts to improve surface characteristics of cement flooring construction, none achieves a combination of improvements which address most or all of the needed improvements.